1. Field of Invention
This invention relates to an internal combustion engine having co-axial pistons on a central yoke. More particularly, this invention relates to reciprocating and pivoting motion produced by cam rotations from a crankshaft.
2. Description of Related Art
Reciprocating piston internal combustion engines have been known for many years. A fundamental operating requirement common to internal combustion engines of the reciprocating piston type is that the reciprocal motion of the pistons must be translated into rotary motion of a crankshaft. This has been achieved most conventionally through a connecting rod attached to each piston at one end through a wrist pin and rotatably mounted to an offset crank arm of the crankshaft at an opposite end.
Other arrangements for converting the reciprocal motion of the piston into rotary motion of a crankshaft have also been proposed. For example, an elongated internally toothed roller gear is attached to a piston and moved to maintain engagement of the teeth with a crankshaft drive gear to impart rotation thereto. Examples of such arrangements are shown in U.S. Pat. Nos. 1,687,744, 4,608,951 and 4,395,977. Such arrangements have heretofore not achieved wide spread commercial acceptability.
Opposed-cylinder internal combustion engines are also known. In such engines, dual pistons are fixed to a common yoke structure or connecting rod arrangement and the pistons are reciprocated within opposed cylinders. Reciprocal motion of the pistons is conventionally translated into rotary motion by an offset crank pin of a crankshaft. U.S. Pat. Nos. 2,172,670 and 2,122,676 disclose engine designs wherein opposed pistons are connected by a connecting rod arrangement. U.S. Pat. No. 4,485,768 discloses a common yoke type internal combustion engine as described and further includes means for altering the stroke and compression ratio of the engine. Specifically, this is achieved by altering the orbital path of a co-axial crank pin and slider relative to a crankshaft axis.
U.S. Pat. No. 4,864,976 which discloses a dual headed piston body formed by a pair of first and second piston heads attached respectively to opposite ends of a central yoke structure. An internally toothed roller gear is mounted for rectilinear movement within the yoke structure. The roller gear engages with a crankshaft drive gear, while control and actuator means are provided for effective synchronized movement of the roller gear within the yoke structure. This arrangement maintains constant engagement of the crankshaft drive gear with the roller gear as the dual-headed piston body reciprocates within the cylinder.
An opposed-cylinder internal combustion engine, as described herein, includes housing with cylindrical chambers on opposite ends of a central connecting portion along a longitudinal cylinder axis of the housing. A manifold piston and a co-axial valve assembly translate independently along the longitudinal cylinder axis within each of the cylindrical chambers. Within the central connection portion, a yoke housing reciprocates along the cylinder axis, while a yoke gear within the yoke housing also perambulates in a transverse direction.
A crankshaft having shaft teeth and shaft cams rotates in the central connecting portion. Yoke teeth on the yoke gear engage the shaft teeth on the crankshaft. The shaft cams extend radially from the outer circumference of the crankshaft. Curved actuator arms engage the shaft cams. The actuator arms pivot on pegs connected to the yoke housing and push components of the co-axial valve assembly.
The crankshaft is connected to at least one flywheel. Flywheel cams protrude axially from the inner rim of the flywheel facing towards the yoke housing. The flywheel cams engage one or more auxiliary shafts to operate a pump or other components in the engine.
In various exemplary embodiments of the devices according to this invention, a compact engine design can be realized.
In various exemplary embodiments, this invention provides a system of flywheel cams, crankshaft cams, rocker arms, a central yoke, co-axial valves and pistons to operate an engine having opposed cylinders.
In various exemplary embodiments, this invention eliminates the need for chain or belt pulleys and other devices for transferring power from the rotating crankshaft.
These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention.